光逆境条件下草莓光合特性的研究

【作者】 迟伟；

【导师】 王荣富；

【作者基本信息】 安徽农业大学 ， 果树学， 2001， 硕士

【摘要】 草莓生长于开放的大田系统，光合生产易受变化光强的影响。过高或过低的光强都会影响草莓的光合生产，从而影响其产量。本研究从遗传种质的角度出发，探讨了草莓在遮荫和光氧化逆境条件下草莓的光合特性变化，为生产上减轻其危害提供理论依据。 1．对5个草莓品种于生育结果期进行遮荫处理，测定其干重的变化。结果发现5个草莓品种之间存在一定的差异。宝交早生干重下降27％，为耐荫品种。硕丰下降了80％，为不耐荫品种。比较两者在遮荫处理后各项生理指标的变化，结果表明：在遮荫处理条件下，宝交早生的光饱和速率下降了20％，而硕丰下降了47％。遮荫处理使两者的表观量子效率都有所提高，分别提高了13％和8％。遮荫处理没有改变宝交早生和硕丰光合速率对温度的响应，但在不同的温度条件下，遮荫处理使宝交早生光合速率下降较少，而硕丰下降较多。进一步测定草莓叶片中的叶绿素含量和可溶性蛋白含量的变化，结果表明：在遮荫条件下，宝交早生的叶绿素含量上升了17％，而硕丰略有增加。两者的Chla/Chlb都有所减少。遮荫处理使宝交早生叶片中可溶性蛋白含量下降了16％，而硕丰则下降了32％。测定光反应的关键指标结果表明：遮荫处理使宝交早生和硕丰的PSII活性分别下降了22.5％和53.7％。测定卡尔文循环的关键酶Rubisco活性，结果表明遮荫处理使两者分别降低了19.6％和35.3％。 2．对5个草莓品种进行人工光氧化处理，并测定各项光合生理指标的变化。结果表明：光氧化处理使明宝的叶绿素含量下降了69％，为光氧化敏感品种。宝交早生叶绿素含量则下降了29％，为耐光氧化品种。明宝的可溶性蛋白含量下降了70％，而硕丰只下降了60％。为探讨两者的光合生理基础的差异，测定了光氧化条件下草莓叶片中氧自由基含量的变化。结果表明：在光氧化条件下草莓叶片中的O₂^-和过氧化氢含量都有所上升。其中硕丰的0。“和过氧化氢分别增加了116％和125兄 而明宝的0。“和过氧化氢分别增加了179％和180％。进一步测定活性氧清除的关键酶SOD、POD和CAT活性变化。结果表明：在光氧化处理条件下SOD活性先被诱导至一个峰值，然后逐渐下降。POD活性则随处理时间的延长而逐渐升高。CAT活性则随处理时间的延长而下降。三者变化规律明显不同。但与明宝比较，硕丰的酶活性表现更为稳定。为研究光氧化处理下，光能利用效率的变化，测定了光氧化处理下荧光参数的变化。结果表明：光氧化处理使硕丰的光化学效率Fv／F．下降较少，保持了较高的光化学效率。进一步分析荧光的变化发现，在光氧化条件下硕丰较大程度地启动了叶黄素循环等耗散过程，耗散了多余的光能，因而保持了较高的光化学效率。更多还原

【Abstract】 The strawberries, which are planted infield, are often affected by light. Too high or low light leads to a reduction in the rate of photosynthesis and therefore a reduction in the rate of growth .The physiological changes of strawberries under shading and photooxidition were studied in this research. 1. Five strawberry varieties were treated under shading condition and dry weight was measured . It had been found that there were some differences aniong them. Baojiaozaosheng whose dry weight decreased by 27% was considered as variety with strong shading tolerance. Shuofeng whose weight decreased by 80% was considered as variety with less shading tolerance .The physiological index of them was compared after shading treatment. The results showed that under shading condition, the net photosynthesis rate of Baojiaozaosheng decreased by 20% while that of Shuofeng decreased by 47%. However, the AQY of them was enhanced by 13%and 8%, respectively. The shading treatment did not change the response of photosynthesis rate to temperature at the two varieties, but at different temperature, the decrease of photosynthesis rate of Baojiaozaosheng under shading condition was less that that of Shuofeng . The chlorophyll content and soluble protein content were also determined. The chlorophyll content Baojiaozaosheng was enhanced by 17% while that of Shuofeng was enhanced less under shading condition. The Chla/Chlb decrease less. The soluble protein of Baojiaozaosheng decreased by 16% while that of Shuofeng decreased by 32%. The PSII activity, the key index of photochemical reaction, was also measured .The PSII activity of Baojiaozaosheng and Shuofeng decreased by 22. 5%and 53. 7% respectively under shading condition. The activity of Rubisco was determined and it was found that the Rubisco activity of the two varieties decreased by 19. 6%and 35. 3% respectively. 2. Five strawberry varieties were treated under photooxidition condition and their physiology index was measured. The results revealed that Mingbao whose chlorophyll content decreased by 69% was considered as photooxidition sensitive variety. Shuofeng whose chlorophyll content decrease by 29% was considered as photooxdition tolerant variety. The soluble protein content of Mingbao decreased by 70% while that of Shuofeng decreased by 60%. To study the physiology basis, The active oxygen of strawberry under photooxidition condition was determined. The results showed that:the 02~ and I~1202 were enhanced by l16%and 125% respectively while those of Mingbao were enhanced by 179%and 180% respectively. The activity of active oxygen scavenger including SOD, POD and CAT were determined .The results showed that under photooxidition condition SOD activity was induced to a highlight then decreased progressively. POD activity was enhanced progress while CAT activity decreased progressively under photooxidition condition. There was significant difference among them. Compared with Mingbao, the scavenger activity of Shuofeng was kept steady . The fluorescence value was also determined in order to study the photochemical efficiency under photooxdition condition .The results showed that under photooxdition condition, Fv/Fm decreased less on Shuofeng compared with Mingbao. The fluorescence quench was also determined and the results showed that Shuofeng started the xanthyll cycle intensively to clear off more energy and it was the reason that Shuofeng kept higher photochemical efficiency.更多还原